4 files changed, 351 insertions, 0 deletions

diff --git a/src/Bindings/CMakeLists.txt b/src/Bindings/CMakeLists.txt
index 673109ffa..a53e82581 100644
--- a/src/Bindings/CMakeLists.txt
+++ b/src/Bindings/CMakeLists.txt
@@ -8,6 +8,7 @@ SET (SRCS
 	Bindings.cpp
 	DeprecatedBindings.cpp
 	LuaChunkStay.cpp
+	LuaJson.cpp
 	LuaNameLookup.cpp
 	LuaServerHandle.cpp
 	LuaState.cpp
@@ -30,6 +31,7 @@ SET (HDRS
 	DeprecatedBindings.h
 	LuaChunkStay.h
 	LuaFunctions.h
+	LuaJson.h
 	LuaNameLookup.h
 	LuaServerHandle.h
 	LuaState.h
diff --git a/src/Bindings/LuaJson.cpp b/src/Bindings/LuaJson.cpp
new file mode 100644
index 000000000..4fa16273c
--- /dev/null
+++ b/src/Bindings/LuaJson.cpp
@@ -0,0 +1,315 @@
+
+// LuaJson.cpp
+
+// Implements the Json exposure bindings to Lua
+
+#include "Globals.h"
+#include <sstream>
+#include "LuaJson.h"
+#include "LuaState.h"
+#include "tolua++/include/tolua++.h"
+#include "json/json.h"
+
+
+
+
+
+// fwd:
+
+static void PushJsonValue(const Json::Value & a_Value, cLuaState & a_LuaState);
+static Json::Value JsonSerializeValue(cLuaState & a_LuaState);
+
+
+
+
+
+/** Pushes the specified Json array as a table on top of the specified Lua state.
+Assumes that a_Value is an array. */
+static void PushJsonArray(const Json::Value & a_Value, cLuaState & a_LuaState)
+{
+	// Create the appropriately-sized Lua table:
+	lua_createtable(a_LuaState, static_cast<int>(a_Value.size()), 0);
+
+	// Insert each value to the appropriate index (1-based):
+	int idx = 1;
+	for (const auto & v: a_Value)
+	{
+		// Include Json null values in the array - it will have holes, but indices will stay the same
+		PushJsonValue(v, a_LuaState);
+		lua_rawseti(a_LuaState, -2, idx);
+		idx += 1;
+	}  // for v: a_Value[]
+}
+
+
+
+
+
+/** Pushes the specified Json object as a table on top of the specified Lua state.
+Assumes that a_Value is an object. */
+static void PushJsonObject(const Json::Value & a_Value, cLuaState & a_LuaState)
+{
+	// Create the appropriately-sized Lua table:
+	lua_createtable(a_LuaState, 0, static_cast<int>(a_Value.size()));
+
+	// Json::Value has no means of iterating over children with their names included.
+	// We need to iterate over names and "find" them in the object again:
+	auto names = a_Value.getMemberNames();
+	for (const auto & n: names)
+	{
+		auto v = a_Value[n];
+		if (v.isNull())
+		{
+			// Skip null values
+			continue;
+		}
+
+		// Set the value in Lua's table:
+		a_LuaState.Push(n);
+		PushJsonValue(v, a_LuaState);
+		lua_rawset(a_LuaState, -3);
+	}  // for itr - a_Value[]
+}
+
+
+
+
+
+/** Pushes the specified Json value as an appropriate type on top of the specified Lua state. */
+void PushJsonValue(const Json::Value & a_Value, cLuaState & a_LuaState)
+{
+	switch (a_Value.type())
+	{
+		case Json::nullValue:
+		{
+			a_LuaState.PushNil();
+			break;
+		}
+
+		case Json::intValue:
+		case Json::uintValue:
+		case Json::realValue:
+		{
+			a_LuaState.Push(static_cast<lua_Number>(a_Value.asDouble()));
+			break;
+		}
+
+		case Json::booleanValue:
+		{
+			a_LuaState.Push(a_Value.asBool());
+			break;
+		}
+
+		case Json::stringValue:
+		{
+			a_LuaState.Push(a_Value.asString());
+			break;
+		}
+
+		case Json::arrayValue:
+		{
+			PushJsonArray(a_Value, a_LuaState);
+			break;
+		}
+
+		case Json::objectValue:
+		{
+			PushJsonObject(a_Value, a_LuaState);
+			break;
+		}
+	}  // switch (v.type())
+}
+
+
+
+
+
+/** Serializes the Lua table at the top of the specified Lua state's stack into a Json value.
+Lets jsoncpp decides whether to serialize into an object or an array. */
+static Json::Value JsonSerializeTable(cLuaState & a_LuaState)
+{
+	Json::Value res;
+	lua_pushnil(a_LuaState);
+	while (lua_next(a_LuaState, -2) != 0)
+	{
+		if (lua_type(a_LuaState, -2) == LUA_TNUMBER)
+		{
+			int idx;
+			a_LuaState.GetStackValue(-2, idx);
+			res[idx - 1] = JsonSerializeValue(a_LuaState);
+		}
+		else
+		{
+			AString name;
+			if (a_LuaState.GetStackValue(-2, name))
+			{
+				res[name] = JsonSerializeValue(a_LuaState);
+			}
+		}
+		lua_pop(a_LuaState, 1);
+	}
+	return res;
+}
+
+
+
+
+
+/** Serializes the Lua value at the top of the specified Lua state into a Json value. */
+static Json::Value JsonSerializeValue(cLuaState & a_LuaState)
+{
+	switch (lua_type(a_LuaState, -1))
+	{
+		case LUA_TNUMBER:
+		{
+			lua_Number v;
+			a_LuaState.GetStackValue(-1, v);
+			return Json::Value(v);
+		}
+		case LUA_TSTRING:
+		{
+			AString v;
+			a_LuaState.GetStackValue(-1, v);
+			return Json::Value(v);
+		}
+		case LUA_TTABLE:
+		{
+			return JsonSerializeTable(a_LuaState);
+		}
+		default:
+		{
+			LOGD("Attempting to serialize an unhandled Lua value type: %d", lua_type(a_LuaState, -1));
+			return Json::Value(Json::nullValue);
+		}
+	}
+}
+
+
+
+
+
+static int tolua_cJson_Parse(lua_State * a_LuaState)
+{
+	// Function signature:
+	// cJson:Parse("string") -> table
+
+	// Check the param types:
+	cLuaState L(a_LuaState);
+	if (
+		!L.CheckParamUserTable(1, "cJson") ||
+		!L.CheckParamString(2) ||
+		!L.CheckParamEnd(3)
+	)
+	{
+		return 0;
+	}
+
+	// Get the input string:
+	AString input;
+	if (!L.GetStackValue(2, input))
+	{
+		LOGWARNING("cJson:Parse(): Cannot read input string");
+		L.LogStackTrace();
+		return 0;
+	}
+
+	// Parse the string:
+	Json::Value root;
+	Json::Reader reader;
+	if (!reader.parse(input, root, false))
+	{
+		L.PushNil();
+		L.Push(Printf("Parsing Json failed: %s", reader.getFormattedErrorMessages().c_str()));
+		return 2;
+	}
+
+	// Push the Json value onto Lua stack:
+	PushJsonValue(root, L);
+	return 1;
+}
+
+
+
+
+
+static int tolua_cJson_Serialize(lua_State * a_LuaState)
+{
+	// Function signature:
+	// cJson:Serialize({table}, [{option1 = value1, option2 = value2}]) -> string
+
+	// Check the param types:
+	cLuaState L(a_LuaState);
+	if (
+		!L.CheckParamUserTable(1, "cJson") ||
+		!L.CheckParamTable(2) ||
+		!L.CheckParamEnd(4)
+	)
+	{
+		return 0;
+	}
+
+	// Push the table to the top of the Lua stack, and call the serializing function:
+	lua_pushvalue(L, 2);
+	Json::Value root = JsonSerializeValue(L);
+	lua_pop(L, 1);
+
+	// Create the writer, with all properties (optional param 3) applied to it:
+	Json::StreamWriterBuilder builder;
+	if (lua_istable(L, 3))
+	{
+		lua_pushnil(L);
+		while (lua_next(L, -2) != 0)
+		{
+			if (lua_type(L, -2) == LUA_TSTRING)
+			{
+				AString propName, propValue;
+				if (L.GetStackValues(-2, propName, propValue))
+				{
+					builder[propName] = propValue;
+				}
+			}
+			lua_pop(L, 1);
+		}
+		// Check for invalid settings:
+		Json::Value invalid;
+		if (!builder.validate(&invalid))
+		{
+			LOGINFO("cJson:Serialize(): detected invalid settings:");
+			for (const auto & n: invalid.getMemberNames())
+			{
+				LOGINFO("  \"%s\" (\"%s\")", n.c_str(), invalid[n].asCString());
+			}
+		}
+	}
+	auto writer(builder.newStreamWriter());
+
+	// Serialize the string and push it as the return value:
+	std::stringstream ss;
+	writer->write(root, &ss);
+	L.Push(ss.str());
+	return 1;
+}
+
+
+
+
+
+void cLuaJson::Bind(cLuaState & a_LuaState)
+{
+	tolua_beginmodule(a_LuaState, nullptr);
+
+		// Create the cJson API class:
+		tolua_usertype(a_LuaState, "cJson");
+		tolua_cclass(a_LuaState, "cJson", "cJson", "", nullptr);
+
+		// Fill in the functions (alpha-sorted):
+		tolua_beginmodule(a_LuaState, "cJson");
+			tolua_function(a_LuaState, "Parse",     tolua_cJson_Parse);
+			tolua_function(a_LuaState, "Serialize", tolua_cJson_Serialize);
+		tolua_endmodule(a_LuaState);
+	tolua_endmodule(a_LuaState);
+}
+
+
+
+
diff --git a/src/Bindings/LuaJson.h b/src/Bindings/LuaJson.h
new file mode 100644
index 000000000..6ec8110bc
--- /dev/null
+++ b/src/Bindings/LuaJson.h
@@ -0,0 +1,32 @@
+
+// LuaJson.h
+
+// Declares the Json exposure bindings to Lua
+
+
+
+
+
+#pragma once
+
+
+
+
+
+// fwd:
+class cLuaState;
+
+
+
+
+
+class cLuaJson
+{
+public:
+	/** Registers the Json library in the specified Lua state. */
+	static void Bind(cLuaState & a_LuaState);
+};
+
+
+
+
diff --git a/src/Bindings/LuaState.cpp b/src/Bindings/LuaState.cpp
index 40cb19304..b03dccad0 100644
--- a/src/Bindings/LuaState.cpp
+++ b/src/Bindings/LuaState.cpp
@@ -16,6 +16,7 @@ extern "C"
 #include "Bindings.h"
 #include "ManualBindings.h"
 #include "DeprecatedBindings.h"
+#include "LuaJson.h"
 #include "../Entities/Entity.h"
 #include "../BlockEntities/BlockEntity.h"
 
@@ -180,6 +181,7 @@ void cLuaState::RegisterAPILibs(void)
 	tolua_AllToLua_open(m_LuaState);
 	cManualBindings::Bind(m_LuaState);
 	DeprecatedBindings::Bind(m_LuaState);
+	cLuaJson::Bind(*this);
 	luaopen_lsqlite3(m_LuaState);
 	luaopen_lxp(m_LuaState);
 }